The present invention relates generally to a semiconductor memory device and a method of fabricating the same, and more particularly relates to a semiconductor memory device capable of inhibiting generation of etching damage caused during a process of fabricating a semiconductor memory device, and a method of fabricating the same.
In semiconductor memory devices, a flash memory device comprises a plurality of strings. In each string, memory cells are disposed in serial. The string is formed on an active region, and an isolation layer is formed between the strings so that the strings are electrically isolated from each other.
A method for fabricating a flash memory device is illustrated in detail as follows.
On a semiconductor substrate, a gate insulating layer, a first conductive layer to be used for forming a floating gate, a dielectric layer, a second conductive layer to be used for forming a control gate and a gate mask pattern are sequentially formed. An etching process is performed according to the gate mask pattern to form an isolation trench on the semiconductor substrate. In particular, in the etching process performed for forming the trench, side walls of the first conductive layer and the gate insulating layer are exposed so that an etching damage can be generated.
In addition, after the trench is formed, an oxidation process can be performed for compensating for etching damage in the trench. At this time, a “bird's beak” phenomenon, in which the thickness of both ends of the exposed gate insulating layer is increased, can be generated.